System And A Method For Filling Tubes In A Tube-Filling Machine

ABSTRACT

The system for filling tubes in a tube-filling machine comprises a closed-ring line activated with alternating motion which bears holders destined to receive upturned tubes, with an open end thereof facing upwards in order to receive a nozzle destined to inject into the tube, after raising of the holder-tube group, a batch of a liquid or paste solution. The nozzle is supplied by a volumetric filler, a cylinder of which is connectable, with consent of an associated switching valve, either with a product supply tank or with the nozzle. The holder, the piston of the volumetric filler and the switching valve are activated by corresponding electric actuators by means of a command, management and control unit according to data, processed by the unit, respectively defining a format of the tube, the diameter of the cylinder of the volumetric filler, the viscosity of the product, the batched amount of the product and the number of tubes to be filled per unit of time.

BACKGROUND OF THE INVENTION

The invention relates to a system and a method for batching a product (liquid and/or pasty solutions) at a same time as filling tubes in an automatic tube-filling machine.

Tube-filling machines include a conveyor line, activated in alternating motion, which bears equidistanced holders, each holder being destined to receive a head of an empty tube provided with a relative cap, such as to keep the tube vertically-arranged with the posterior part thereof open and facing upwards.

The line comprises various work stations:

a tube-loading station;

a tube-orientating station;

a tube-filling station (batching the product);

various stations for closing the posterior end of the tube, conformed according to the nature of the material (for example, aluminum, plastic, laminates, etc.) that the tube is made of;

a tube-coding station;

a station for closing the posterior edge of the tube;

a reject station for discarding tubes considered to be defective;

a full-tube outlet station.

At least an injecting nozzle (if the tube-filling machine is single-channel) is comprised in the filling station, which nozzle is downwardly-orientated, and which nozzle is centered with respect to the posterior mouth of the tube positioned in the station; in suitable phase relation with the position, the holder-lift, in which the tube is inserted, is raised by suitable first activating means, such as to insert the nozzle in the tube.

At this point the nozzle is supplied with the product, in phase relation with the holder-lift, and therefore the tube, up to completion of the filling thereof; completion of the lowering of the holder leads to exit of the nozzle from the tube.

The nozzle is connected to a volumetric filler, constituted by a cylinder in which a piston sealedly slides, which piston is borne by a stem that projects from a head of the cylinder, and which is movable axially by means of second activating means.

The remaining head of the cylinder affords two through-holes, which with the aid of a switching valve adjacent to the head are alternatively connected one to a product supply tank (liquid and/or paste solution) and the other with the nozzle. The valve is switched by third activating means.

In a first phase the batcher aspirates the product from the tank: the length of the piston travel determines the batched amount of the product; when the valve switches, which is performed in phase relation with the inversion of the piston movement, the product is compressed by the piston and is consequently fed to the nozzle and fills the tube.

The first, second and third activating means are constituted by mechanical cams which are driven by relative actuators, conformed such as to respect the above-described mutual phase relations, obviously over the machine cycle of the filling station.

In particular, the second activating means cause: the piston travel (thus the batched amount of the product); the speed of the piston in the cylinder during the product aspiration phase; and the speed of the piston on compression of the product directed towards the nozzle.

As specified, the holder-lift in the filling station is raised towards the nozzle and thereafter lowered during the filling of the tube borne by the holder.

The length of the holder-lift stroke is a function of the tube size and the batched amount of the product; the law of movement with which the holder-lift is lowered is strictly connected to the speed with which the piston compresses the product.

The product inserted into the tubes can exhibit a viscosity comprised within a broad spectrum. The viscosity might be comparable to water, or it might be high as in very pasty creams.

In the case of low viscosity (compatibly with the inertia of the piston and the cam moving it) the aspiration is fast and the compression slow in order to prevent even partial emptying of the conduit connecting the nozzle with the batcher. If the product is highly viscous, the speed of product aspiration has to be such as to prevent cavitation in the product, while the compression speed is as rapid as possible considering the inertia in the masses involved.

To sum up, in the prior art the variation of the batch of product, comprised in the operating volume of the batcher cylinder, and if the batch is to be optimized, requires the replacement of the cams of the second activating means. In this way, batch-for-batch, on variation of the viscosity it is possible to establish various ranges of viscosity for which predetermined speeds of aspiration and compression can be attributed to the piston. This can be obtained by corresponding cam profiles in the second activating means.

This is a compromise solution which, among other things, does not resolve the mentioned drawbacks. In fact, if a following product has a viscosity in a different range from the previous one, at least the cams of the first and second activating means have to be changed.

SUMMARY OF THE INVENTION

The advantage of the present invention is that it provides a system which in a tube-filling machine such as in the preamble hereto, using a cylinder/piston batching cylinder, and according to the size of the tube, the viscosity of the product and the productivity of the machine itself, enabling the aspirating/pumping strokes of the piston working inside the cylinder to be regulated, as well as the aspiration and compression speeds of the piston itself, the switching between the product aspiration phase and the product compressing stage, the travel of the holder-lift and the speed of rising and lowering of the holder-lift.

A further advantage of the invention is that it provides a system which can be activated by means of instructions provided directly by an operator or calculated from previously-stored data relating to the tube, the batch, the product to be processed by the tube-filling machine.

A further advantage of the invention is to actuate the system using reliable and functional organs, managed by means of algorithms which process data such as to use the technical-functional aspects of the technical expert in the sector and deducible from experience and/or experimental testing, such as the speed of the aspirating/pumping piston according to the product viscosity, such as to optimize the productivity of the tube filling stage, in respect of the tolerances in the batched product.

A further advantage of the invention is to provide a method, actuable with the present system, which enables the batching of tubes to be optimized while changing the tube format, the format of the batcher, the viscosity of the product, the batched amount of the product and the productivity required, compatibly with the organs used, all of which is obtainable without replacing mechanical parts, such as cams or specially-shaped devices for various formats.

The above-described advantages are obtained by means of a system for filling tubes in a tube-filling machine and by means of a method actuated according to the aforementioned system.

The system for filling tubes in a tube-filling machine for filling tubes in a tube-filling machine is of a type comprising a closed-ring line, activated in alternating motion, which line bears equidistanced holders, each conformed such as to receive a head, provided with a cap, of an empty tube arranged vertically with an open posterior end facing upwards, the line comprising at least a station for filling each tube with a batch of product constituted by a liquid or paste solution, which station comprises at least a nozzle for supplying product to the tube located in the station, and first activating means for vertically translating a holder-lift which brings a group comprising the holder and the tube to insert and disinsert the nozzle into and out of the tube, which nozzle is supplied by a volumetric filler of a cylinder-piston type, with the piston being solidly constrained to a stem projecting from a head of the cylinder, the stem being axially moved by second activating means, the cylinder being connectable via a switching valve, adjacent to a remaining head of the cylinder and moved by third activating means, either with a supply tank of the product or with the nozzle, the system comprising a command, management and control unit, destined to receive and process:

data relating to geometric dimensions of the empty tube;

data relating to a diameter of the cylinder;

data relating to a viscosity of the product;

data relating to an amount of a batch of the product with which the tube, situated in the filling station, will be filled;

data relating to a number of tubes to be filled in a given unit of time;

and wherein the first, second and third activating means are constituted by three actuators acting in a suitable phase relation on the holder-lift, the stem and the switching valve, which actuators are activated by signals supplied by the unit in accordance with the data.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics of the invention are set out in the following description, which makes reference to the figures of the accompanying tables of drawings, in which:

FIG. 1 schematically illustrates, in plan view, an arrangement of the work stations of a tube-filling machine;

FIG. 1A schematically illustrates, with reference to station D of FIG. 1, a volumetric filler and electrical-electronic organs and devices associated thereto in order to actuate the proposed system and methods;

FIGS. 2-5 illustrate the same configuration as in FIG. 1 in various work stages;

FIG. 6 is a diagram of the stages which together act to realize the batching of the product inserted in the tube;

FIG. 7 is a schematic lateral view of an empty tube;

FIG. 8 is a flow-chart listing the significant stages of the proposed method.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the figures of the drawings, L denotes a closed-ringed conveyor line of an automatic tube-filling machine, for example a single-channel machine. The line carries, in a known way to an expert of the sector, equidistanced holders 1 each of which is destined to receive the head 2A or shoulder of an empty tube 2 provided with a relative cap 3, such as to keep the tube itself arranged vertically with the open posterior end 2B facing upwards (FIGS. 1A-5).

FIG. 1 denotes various work stations arranged along the line L, among which, in order:

a station C for loading tubes into relative holders 1;

a station O for orientating the tubes;

a station P for cleaning an internal surface of the tubes;

a station D for filling the tubes, with a predetermined batch of product 4 (liquid and/or paste solutions);

various stations R1, R2, R3, R4, for closing and sealing the posterior end of each tube, conformed according to the material (e.g. aluminum, plastic, laminates, etc.) with which each tube is constituted;

a station J for coding the tubes;

a station W for trimming the posterior edge of each tube;

a station K for rejecting tubes which are considered to be defective;

a station E for outletting full tubes 2 from the line.

The present invention is focused on the volumetric filler 10, which is functionally associated to the filling station D, and on the electrical and electronic organs and devices cooperating with the volumetric filler 10.

It therefore follows that the remaining stations, and the means associated thereto, have not been illustrated and described in detail, as they are generally well-known to the expert in the sector and are not relevant to the object of the invention.

The batcher 10 comprises a cylinder 5 in which a piston 6 sealedly runs, borne by a stem 7 exiting from a head 5A of the cylinder 5.

The remaining head 5B of the cylinder affords two through-holes 8, 9 which, with the aid of a switching valve 11, are alternatively connected, one (first position X₁) with a tank 12 for supply (gravity or pressure) of the product and the other (second position X₂) with a pipe 13 connected to a nozzle 14.

The nozzle 14 is connected to the filler station D, faces downwards and is centered with respect to the posterior mouth 2B of an empty tube positioned in the station.

The switching valve 11 is activated by an actuator 15 (signal 3) preferably an electric actuator, supplied by a control, management and command unit 100.

The stem 7, to which the piston 6 is solidly constrained, is activated by an actuator 16, preferably and electric actuator 16, with interposing of an interface mechanism 16A which transforms the rotation of the drive shaft in a direction or in another, into translation of the stem 7 in a direction or in another; the actuator 16 is managed by the unit 100 (signal 2).

As specified in the preamble, the holder 1 disengages from the line L and is raised in the filler station D; this is done by action of a holder-lift 50 bearing the holder 1, which holder-lift 50 is moved by an actuator, preferably an electric actuator, managed by the unit 100 (signal 1).

The switching valve 11, the batcher 10, and the holder-lift 50 are not activated by means of mechanical cams as in the prior art, but are moved respectively by actuators 15, 16, 17 according to laws of movement imposed by the unit 100 as specified herein below.

With reference to FIG. 7, D₁ denotes the tube and H₁ the height of the tube starting from the shoulder 2A thereof; the height H₂ of the product 4 internally of the tube is linked to the batch amount and the diameter D₁.

The difference between the heights H₁ and H₂, denoted by D₁, identifies the minimum closing distance, i.e. the portion of the posterior end of the tube which will be folded and sealed in the stations R₁-R₄.

D₃ denotes the distance, with the holder-lift 50 in the lowered position, between the nozzle and the extremity of the posterior end 2B of the tube.

An interface (or panel) 150 for data entering is functionally connected to the unit 100.

The operator, by means of an appropriate keyboard T, transmits the following data to the unit 100:

geometric characteristics, denoted by reference Y₁, relating to the values D₁, D₂, D₃, H₁, H₂ identifying the size and dimensional characteristics of the tube 2, or associated to the tube (e.g. parameter D₃);

the diameter of the cylinder 5 of the volumetric filler; reference Y₂;

the viscosity of the product 4; reference Y₃;

the value of the batch, i.e. the volume of the product to be inserted in the tube; reference Y₄;

production speed, i.e. the number of batching cycles (i.e. tubes filled in the filler station D) in a given time unit; reference Y₅.

The unit 100, according to the data Y₁, Y₄ determines the height H₂ of the product internally of the tube and, consequently, the height by which the holder-lift 50 will be raised.

The travel of the stem 7, i.e. the piston 5, is calculated according to the data Y₂, Y₄.

Data Y₃ will give the viscosity and Y₅ the productivity, and these are used to calculate the speed of the piston 5 on aspiration of the product 4 by the tank 12, and the speed with which the product is compressed on supply to the nozzle 14.

Obviously a priority is the value of the tolerances established for the value of the batch (aspiration/pumping of the product 4) with respect to the productivity.

FIG. 6 includes, in a machine cycle (360 degrees in mechanical terms) the graphs relating to the piston movements 6 (reference α₁), of the conveyor line L (reference α₂) of the holder-lift 50 (reference α₃) and the switching valve 11 (reference α₄); graphs α₁-α₄ give the mutual phase relations between the various movements.

The following phases are in phase relation with the start of the pause of line L:

the piston 6 completes aspiration of the product (graph α1);

the holder-lift 50 raises the holder 1-tube 2 group with the maximum speed that the motor torque (actuator 17) allows, positioning the nozzle 14 at the bottom of the tube (see FIG. 2).

The final of the above phases is preceded by the completion of the phase of aspiration (see graphs α₁, α₃).

The switching of the valve 11 from the first position X₁ to the second position X2 is set in phase relation with the definition of the raising of the holder-lift 50 and the end of the product aspiration phase; see graph α₄ and FIG. 2.

Following the switching the valve 11, the following occur, in synchrony: the product compression phase, by effect of the piston 6, internally of the cylinder 5, with a consequent exit of the product 4 from the nozzle 14, and me descent of the holder-lift 50 which bears the holder 1-tube 2 group (see FIG. 3 and graphs α₁, α₂).

The descent of the holder-lift 50 is done in two steps, one at constant velocity synchronously with the pumping of the product to the nozzle (FIGS. 3, 4), the other at the maximum velocity allowed by the actuator 17, in order to allow the nozzle 14 to completely exit from the tube 2 (FIG. 5) and to enable the holder 1 to deposit in the relative seating afforded in the line L as quickly as possible.

In phase relation with the moment that divides the two descent phases of the holder-lift 50, the product stops exiting from the nozzle, in consequence of a signal β₄ supplied by the unit 100, connected to the fact that the pump action of piston 6 ceases; the switching valve is then brought into the first position X₁, the line L is moved by a step (corresponding to 120 degrees of the machine) and the piston 6 beings a new aspirating phase.

An example of an operating cycle, obtained using the present method using the above-described and illustrated system, can be deduced from the flow chart of FIG. 8.

The first phase F₁ includes the analysis of data Y₁, Y₂, Y₃, Y₄, Y₅, already described herein above.

The second phase F₁ includes the definition of the holder-lift 50 according to data Y₁ and Y₄.

In the third phase F₃ the value of the descent run of the holder-lift is calculated.

In the fourth phase F₄ it is calculated whether the holder-lift raising time is greater than or equal to the time in which the valve 11 remains in the first position X₁ (aspiration of the batch into the cylinder 5).

If these criteria are satisfied, the batch aspiration time is set to be equal to the lift time of the holder-lift 50 (fifth phase F₅).

If these criteria are not satisfied, a fifth auxiliary stage F₅* is set, in which the batch aspiration time is equal to the time in which the valve 11 remains in the first position X₁.

In the sixth phase, F₅, the time available for batching (injection of the product 4 in the tube 2) is calculated.

In the seventh phase F₇, the pause time of the holder-lift 50 is calculated according to the time required by the valve 11 to switch from the first position X₁ to the second position X₂.

In the eighth phase F8 the cycle time of the holder-lift 50 (rise, pause and descent) is calculated to see whether it is less than or equal to the pause time of the machine (for example 240 machine degrees); if this criterion is not satisfied, the machine cycle velocity is too fast and is considered to be unacceptable.

If the above criteria are satisfied, the percentage calculation (ninth phase F₉) of the time required for aspirating the batch and for pumping the batch is proceeded to, in machine degrees, taking into consideration the data Y₃ relating to the viscosity of the product 4.

The times identify corresponding piston 6 velocities; if (tenth phase F₁₀) this falls within the mechanical limits of the piston 6-stem 7 group and the relative actuator 16, and the holder-lift 50 and the relative actuator 17, the cycle is considered to be valid and operative (eleventh phase F₁₁); if the result is the contrary, the cycle is not accepted (eleventh auxiliary phase F₁₁*).

On changing the tube format, and/or the cylinder diameter 5, and/or the product viscosity, and/or the batch, and/or the productivity, the data Y₁-Y₅ (displayed on the monitor F included in the interface 150) are correspondingly modified and the unit 100, in agreement with the new data, commands the actuators 15, 16, 17 accordingly.

The parameter which varies most frequently is viscosity, such that, taking the tube 2 format, the batch and the cylinder 5-piston 6-valve 11 group to be the same, the unit 100 intervenes to change the speeds of the piston runs 6 (and the descent velocity of the holder-lift 50).

Thus the combination of the unit 100 and the actuators 15, 16, 17 enables “electronic cams” to be realized, with which the valve 11, the piston 6 and the holder-lift 50 can be commanded, in order to optimize the batching and the time required to carry out the batching, thus obviating the drawbacks in the prior art.

The provided system does not include the replacement of mechanical cams, as in the prior art, and is also very versatile indeed as it can be adapted to all possible situations, solely by entering data Y₁-Y₅ in the unit 100.

The provided method is such as to optimize the functioning of the batcher meter 10, in particular in relation to the productivity of the filler station D, and independently of the variations in the data Y₁-Y₅.

The data which identify a tube format, a cylinder 5-piston 6-valve 11 group, a product (via the viscosity thereof), a batch value and a productivity are stored in the unit 100 and can be recalled when identical tube-batching situations arise. 

1) A system for filling tubes in a tube-filling machine of a type comprising a closed-ring line, activated in alternating motion, which line bears equidistanced holders, each conformed such as to receive a head, provided with a cap, of an empty tube arranged vertically with an open posterior end facing upwards, the line comprising at least a station for filling each tube with a batch of product constituted by a liquid or paste solution, which station comprises at least a nozzle for supplying product to the tube located in the station, and first activating means for vertically translating a holder-lift which brings a group comprising the holder and the tube to insert and disinsert the nozzle into and out of the tube, which nozzle is supplied by a volumetric filler of a cylinder-piston type, with the piston being solidly constrained to a stem projecting from a head of the cylinder, the stem being axially moved by second activating means, the cylinder being connectable via a switching valve, adjacent to a remaining head of the cylinder and moved by third activating means, either with a supply tank of the product or with the nozzle, the system comprising a command, management and control unit, destined to receive and process: data relating to geometric dimensions of the empty tube; data relating to a diameter of the cylinder; data relating to a viscosity of the product; data relating to an amount of a batch of the product with which the tube, situated in the filling station, will be filled; data relating to a number of tubes to be filled in a given unit of time; and wherein the first, second and third activating means are constituted by three actuators acting in a suitable phase relation on the holder-lift, the stem and the switching valve, which actuators are activated by signals supplied by the unit in accordance with the data. 2) The system of claim 1, wherein the command signals of the activating actuators respectively of the holder-lift and of the stem of the piston are such as to make a descent of the holder-lift synchronous with the pumping action of the piston. 3) The system of claim 2, wherein the command signal of the activating actuator of the holder-lift defines two phases for descent of the holder-lift, of which a first phase, synchronous with the pumping action of the piston, and a second phase, actuated with the nozzle when unsupplied, to enable exit of the nozzle from the tube. 4) The system of claim 1, wherein the command signal of the activating actuator of the holder-lift is such as to impose a raising of the holder-lift with a maximum speed compatible with a potential of the actuator. 5) The system of claim 3, wherein the command signal of the activating actuator of the holder-lift commands performance of the second phase with a maximum speed compatible with a potential of the actuator. 6) The system of claim 1, wherein the actuators are activated by a same number of electric motors. 7) The system of claim 1, wherein the tank supplies the product contained therein to the cylinder by force of gravity or under pressure. 8) The system of claim 3, wherein the nozzle is provided with an electrically-commanded obturator for activating and deactivating the nozzle, wherein the obturator is brought into a relative deactivated position by means of a signal supplied by the unit at a moment between the two phases. 9) A method actuated according to the system of claim 1, wherein the processing performed by the command and control unit comprises: analysis of data relating to a format of the tube, of data relating to a diameter of the cylinder, of data relating to a batch amount of the product, and of data relating to productivity; calculation of a travel of the holder-lift according to both the data, relating to the format of the tube, and the data relating to the batch; evaluation of a descent run of the holder-lift; verification that a raise time of the holder-lift is greater than or equal to a time in which the switching valve remains in a first position thereof, in which position product is aspirated into the cylinder; equality between the aspirating time of the batch into the cylinder and the holder-lift raise time; evaluation of a time necessary for performing the batching; determination of a pause time of the holder-lift as a function of a time required by the switching valve for passing from the first position for connecting the cylinder with the tank to a second position for connecting the cylinder with the nozzle; verification that a sum of the lift time, the pause time and the descent time of the holder-lift is less than, or equal to, a pause time of the line; percentage calculation, in machine degrees, of a time required for aspirating the batch into the cylinder and for pumping the batch towards the nozzle, all of which is evaluated as a function of the data relating to the viscosity of the product; evaluation of whether the calculation is compatible with the activating organs of the piston and the holder-lift; acceptance of the cycle on receiving a positive response to the preceding point. 10) The system of claim 9, wherein if the lift time of the holder-lift is less than the time in which the switching valve stays in the first position thereof, the raise time of the holder-lift is made equal to the time required for aspirating the batch into the cylinder. 11) The system of claim 9, wherein if a sum of the lift time, pause time and descent time of the holder-lift is greater than a pause time of the line, an operating cycle is considered not valid. 12) The system of claim 9, wherein the operating cycle is considered not valid if a calculation of times necessary for aspirating the batch and for pumping the batch are not compatible with the activating organs of the piston and of the holder-lift. 